
struct GlobalPosition{
    GlobalPosition(double lon, double lat, double alt):
                longtitude(lon), latitude(lat), altitude(alt) {};
    GlobalPosition(){};

    double longtitude;
    double latitude;
    double altitude;
};

void wgs84_to_enu(double lat, double lon, double alt, 
                  double lat_ref, double lon_ref, double alt_ref,
                  double& north, double& east, double& down);

void enu_to_wgs84(double north, double east, double down, 
                  double lat_ref, double lon_ref, double alt_ref,
                  double& lat, double& lon, double& alt);

